Do you know what a factorial is? 3 factorial is written as 3! and is defined as 3! = 3x2x1. So three factorial equals 6. That’s easy. What about 100! Or 124! O

Do you know what a factorial is? 3 factorial is written as 3! and is defined as 3! = 3x2x1. So three factorial equals 6. That’s easy. What about 100! Or 124! Obviously you could calculate that by multiplying all the numbers but that’s slow. A quicker way is to use Ramanujan’s formula which will give you an answer with much less calculation. The catch is that the answer may not be exactly correct, just a very good approximation. For many applications this is not an issue, and a faster calculation is more useful than a slightly more accurate answer.